Carbamate containing acid nickel plating bath



United States Patent 3,429,789 CARBAMATE CONTAINING ACID NICKEL PLATING BATH Barnet D. Ostrow and Fred I. Nobel, Roslyn, N.Y., assignors to Lea-Ronal, Inc., a corporation of New York No Drawing. Filed Oct. 19, 1965, Ser. No. 498,077 U.S. Cl. 20449 11 Claims Int. Cl. C23b 5/08 ABSTRACT OF THE DISCLOSURE Electrolytes for the electrodeposition of nickel comprising as leveling agent certain carbamate substituted acetylenic alcohols which may have one or more alkoxy groups therein. Various sulfo-oxygen compounds may be present as cooperating additives.

The present invention is directed to acid nickel plating baths, and more particularly to the presence therein of substances adapted to improve the operating characteristics of semi-bright and fully bright baths.

Considerable work has been done in the past in attempts to improve such baths, some of which have been successful to a certain degree, but it is highly desirable that still further improvement be affected. In commercial semi-bright and bright nickel plating it is necessary that a high degree of leveling of the deposit be obtained. The lack of adequate leveling increases the amount of mechanical finishing that must be performed on the basis metal prior to or after plating. It is also important that the ability of the bath to produce leveling extend over a wide current density range. In prior art bright nickel plating many acetylenic compounds were proposed. However, many such acetylenic compounds did not exhibit the desired ability to level and brighten the deposit over a wide commercially desirable current density range.

Among such compounds, acetylenic alcohols such as propargyl alcohol, butyne diol, and substituted acetylenic alcohols have been proposed in attempts to overcome the deficiencies of this group of materials, since many such alcohols have poor low current leveling ability and tend to produce skip plate badly. Butyne diol, for example, has poor low current density leveling. It has been proposed to substitute epoxy groups onto the acetylenic alcohol; while such substituents improve the brightening and leveling to a degree in the low current density areas, there' is but little improvement in the low current density skip plating.

It has also been proposed to modify the acetylenic alcohols by the introduction of an acid radical to form an ester such as butynoxy 1,4 acetic acid. Such introduction tends to improve the leveling ability of the modified compounds over the acetylenic alcohols. However, the tendency to form low current density skip plate is greatly increased.

The use of alkyneoxyalkaneamides and of alkadiyneoxyalkaneamides in such baths has also been proposed. But the leveling ability of these substances appears to be inferior to even the epoxy substituted compounds. Also such baths leave much to be desired in the elimination of skip plate in low current density areas.

The present invention is intended and adapted to overcome the disadvantages inherent in acid nickel plating baths of the prior art, it being among the objects thereof to provide an additive which will substantially improve the leveling of the deposits, and which is adapted to virtually eliminate skip plating.

In practicing the invention there is introduced into the usual baths a small amount of a carbamate substi- 3,429,789 Patented Feb. 25, 1969 tuted acetylenic alcohol, either a monol or a diol. It also contemplates the introduction of one or more alkoxy groups into the modified alcohol, such as ethoxy or propoxy radicals. Baths made therewith produce nickel deposits having a high degree of level even in low current density areas and with an effective decrease in the tendency to skip plate. These acetylenic carbamates are characterized by the following general formulae:

wherein R and R are selected from the class consisting of H and alkyl having 1 to 12 carbon atoms and substituted products thereof, X is selected from the class consisting of ethoxy and propoxy, n is 0 to 12, and Y is selected from the class consisting of The longer chain acetylenic carbamates are not as soluble as the corresponding alcohols. For example, butyne 2-1,4 dicarbamate is not as soluble as butynediol. The shorter chain homologue l-propyne, 3-carbamate is more water soluble than the above butyne compound. The introduction into the molecule of alkoxy groups not only increases the water solubility but also greatly improves the leveling characteristics of the compounds.

The acetylenic carbamates may be used in the bath alone or in conjunction with known sulfo-oxygen compounds, sulfonamides, sulfonimides, or other types of compounds to produce fully bright platings. They may be used in the standard Watts, chloride, fluoborate or sulfamate baths. Such bath may contain wetting agents such as sodium lauryl sulfate, sodium Z-ethylhexyl sulfate, sodium octyl sulfonate, and various others, known to the art.

Typical acetylenic carbamates which are illustrative of the class are as follows:

1-propyne-3 carbamate 1-propyne-3 diethoxy carbamate l-butyne-3 methyl-3 carbamate l-butyne-3 methyl-3 dipropoxy carbamate Z-butyne-l 01-4 carbamate Z-butyne-l ol-4 ethoxy carbamate 2-butyne-l,4 dicarbamate 2-butyne-1,4 tetra ethoxy dicarbamate l-pentyne-3 methyl-3-triethoxy carbamate 1-propyne3 dipropoxy carbamate The carbamates may be used in amounts up to about 1.0 gram per liter, or more if desired. Preferably, there is present about 0.0007 to 1.0 gram per liter when used without other additives or with other types of carrier brighteners than sulfooxygen compounds. When used in conjunction with sulfooxygen compounds, the amount may be about 0.002 to 0.7 gram per liter.

In many cases, to produce the maximum brightness and level, it is desirable to have present one or more additives. Such additional substances may be sulfonamides and/or sulfonimides. It is also desirable to have present aromatic sulfonic acids having one or more sulfonic groups.

In many cases, it is desirable to have present at least one other additive. Such additional substances are certain sulfonamides and sulfonimides. It is also desirable to have present aromatic sulfonic acids having one or more sulfonic groups.

These constituents may be present in the bath in 5 quantities varying over relatively wide limits, but for best results comparatively large amounts of the sulfonamides or sulfonimides are used. Varying the proportions of the constitutents may enhance one physical property over another. For example, with higher concentrations of acetylenic ethoxylated compounds, leveling may be still further improved with some reduction in covering power.

The sulfonamides and sulfonimides are well known compounds; they include the disulfonamides. It is possible to use aliphatic or aromatic derivatives; however, the most commonly known compounds are those of benzene and naphthalene. They may have substituent groups which are inert in the bath and which do not adversely affect the characteristics of the deposit. They are used in the bath in amounts from about 0.2 gram per liter to saturation and the larger amounts are not detrimental to the operation.

Among the sulfonic acids, it has been found that methylene bis-naphthalene or benzene sulfonic acids together with a sulfonamide or sulfonimide produce improved brightness and leveling when used in conjunction with the ethoxylated acetylenics. The amounts of these substances may vary widely and as little as 0.05 grams per liter has been found suflicient to exert their beneficial effect. Up to 50 grams per liter or more of the sulfonics may be used.

Typical other sulfonic compounds are the sodium salts of benzene sulfonic, naphthalene trisulfonic, bromo benzene sulfonic, allyl sulfonic and vinyl sulfonic acids and O-sulfo benzaldehyde sodium salt. Among the sulfona- 35 mides and sulfonimides typical compounds are benzene sulfonamide, benzene disulfonamide, O-benzoyl sulfonimide, and allyl sulfonamide.

The following are typical plating baths made in accordance with the present invention:

m e 2-butyne 1-4 tetraethoxy dicarbamate- 1-propyne-3 carbamate Sodium lauryl sulfate... 0. 25 Chloral hydrate Plating is conducted in a pH range of about 3.0 to 5.0. The temperature of the bath is maintained at about to F., with agitation of the solution.

The amounts of the above-named constituents are 65 grams per liter of aqueous solution. The conditions used in the plating operation are typical in the industry, such as temperature, voltage, current density and others. The results obtained are uniformly superior to those resulting from the use of prior art'baths.

What is claimed is:

1. An aqueous acid nickel plating bath of the sulfamate, sulfate or chloride type containing an effective amount to improve leveling of an acetylenic carbamate soluble in the bath selected from the class consisting of:

and

2. A nickel plating bath according to claim 1 in which said carbamate is present in amounts from about 0.002 to 0.7 gram per liter.

3. A nickel plating bath according to claim 2 in which there is present a sulfonic acid.

4. A nickel plating bath according to claim 2 in which there is present a sulfonic acid in the amount of about 0.05 gram per liter up to the limit of solubility thereof.

5. A nickel plating bath according to claim 1 in which there is present a compound selected from the class consisting of sulfonamides and sulfonimides.

6. A nickel plating bath according to claim 5 in which there is present a sulfonic acid.

7. A nickel plating bath according to claim 5 in which there is present a sulfonic acid in the amount of at least 0.2 gram per liter.

8. A nickel plating bath according to claim 1 in which said carbamate is present in amounts from about 0.0007 to 1.0 gram per liter.

9. A nickel plating bath according to claim 1 in which there is present a compound selected from the class consisting of a sulfonic acid.

10. A nickel plating bath according to claim 1 in which there is present a compound selected from the class consisting of a sulfonic acid in the amount of about 50 grams per liter.

11. A nickel plating bath according to claim 1 in which the carbamate is tat-acetylenic ethoxy carbamate.

References Cited UNITED STATES PATENTS ROBERT K. MIHALEK, Primary Examiner.

G. L. KAPLAN, Assistant Examiner.

U.S. Cl. X.R. 

